[Reviewer Andy] Normalize public identifiers before checking authentication status

Andy

Can you review.  The issue is similar to one we hit recently in the registration store, in that sometimes there are extra parameters in the URI that must be stripped out to get to an identifier we can check for authentication.

I decided to specify the interface to the Flow object as taking a URI and making the Flow object responsible for normalizing this down to an identifier that can be checked.

I've run the existing UTs over this, and update one of the edge proxy test cases to test this specific situation.

Mike